Measuring instrument having automatic zeroizing mechanism



Aug. 20, 1935. J. G. PAULIN 2,011,774

MEASURING INSTRUMENT HAVING AUTOMATIC ZEROIZING MECHANISM Filed Jan. 21, 1951 28heets-Sheet 1 Aug. 20, 1935.

MEASURING INSTRUMENT HAVING AUT OMATI C ZEROIZING MECHANISM Filed Jan. 21, 1951 J. G. PAULIN 2,011,774

2 Sheets-Sheet 2 T Patented Aug. 20, 1935 i-H DJ S E AT N OFFICE f MEASURING TNSTRUMENT HAVING AUTO;-

MATIC ZEROIZING MECHANISM Josua Gabriel Paulin, Eskilstuna, Sweden Application January 21, 193i, Serial No. 510,266

In Sweden January 30, 1930 i s Claims. (Cl. 73-151 flhe present invention relatesto instruments,

for measuring variable'forces. More particularly it-relates to such instruments, as aneroid barometers, in which a measuring member movable .5under the influence of said forces is automatically restored to a certain middleposition by means of a zeroizing mechanism for the reading of the instrument according to the zero method.- The invention has for its object to render possible an e lo easy reading .or estimation of the rapidity of fluctuation of the force measured. The possibility of ascertaining the rapidity, for instance, of the' fluctuations in the atmospheric pressure measured by an aneroid is in certain cases of great '-value. By means of an aneroid designed in this manner and used as an altitude meter in an air:

craft one-may, by. way of example, continually control therate of the rising or the falling motion of the aircraft, besideswhich the instrument may be'used as a so-called statoscope adapted to ascermains constant,'tal es up a certain zero position but which, upon each zeroizing impulse of the same direction as the next preceding zeroizing' impulse, is given a certain deflection in the corre- 'sponding. direction and, upon eachzeroizing impulse of opposite direction to the next preceding impulse, is re'stored to its zero position. Preferably said pointer or indicator is 'then'provided with a'looking device being under the control of the zeroizing mechanism andshiftable into'twoopposite locking positions." Said locking device exerts in the two' locking positions mutually opposite unidirectional locking actions upon the pointer.

I The invention will be more closely described with reference to the accompanying drawings 45 showing an embodiment of the invention. Figure 1 is a plan 'view of those parts of the zeroizing de vice of the instrument which are concerned in the invention. Figure 2 is a detail ofFigu're 1. Figure 3 is adetail of the zeroizing device during- 55 with the barometer associated therewith, and Fig.

7 is a fragmentary plan detail of the arrangement shown in Fig. 6. I

The shownembodiinent is assumed to'relate to an' aneroid-barometer in which the air pressure 60 actuating the diaphragm is balanced by an automaticallyadjustable counterforce which, byway of'example in a manner known per se, may be constitutedby the tension of a counter spring 28 which is secured at one end to the diaphragm 21 by means of afixture'29 and at the other end to a nut screwed upon a micrometer screw which is secured to the shaft Inf 3, toothed wheel 2. The nut 30 is provided with a laterally extending arm engaging 'a guide bar in the frame softhat the nut without being turned, is displaced axially by the turning of the micrometer screw.- The alteration of the spring tension may, however, also be brought about by means ofother devices actingin the desired manner. The wheel 2 is'circumferentially provided with teeth 3'and is shifted step by step alternatively in the one or the other direction by means of a stepping mechanism actu-- ated by periodical impulses and comprising two pawls i and 4' which are pivoted at 5 and 5 respectively on a support 6 carried by arms 6 which in turn are pivoted, at 38 (Fig. 6) on the instru ment frame said pawls serving to transmit said impulses to the toothedwheel 3. Said'support is provided with an arm 1 extending backwards which by its outer end carries a small wheel. The support 6 is periodically pushed towards a toothed wheel 8 against the action of a spring not shown which wheel rotates in the direction of the arrow at a-constant velocity the teeth then successively engaging the end of'the arm I. The pawls 4 and 4" are normally held in the positions shown in Figure 1 by a helical spring 9 fixed under tension between rearwardly extending projections of the pawls. Between the pawls 4, 4' a member 10 forming anedge is disposed and adapted to move in the middle plane of the instrument and pivotally mounted in the frame at 38 (see Fig. 6). Under the influence of a spring l0 said edge normally takes up an upper position shown in Figure 1 immediately in front of two arms I I and II extending towards the middle'from the pawls. In front of the member H] a cuspidated member I 2 is movable, which member is formed at the end of a tendency pointer 32 carried by a shaft 33, which shaft is suspended between two helical springs 34 stretched in opposite directions to the frame and tending to turn the shaft about its axis in a certain direction. To a small pulley'secured to the shaft 33 are fastened the ends of two wires 35 which, on theother hand, are connected with other wires 31 stretched between stationary points in theframe and arms 36 extending from a fixture 29. The arrangement is such that an increase of the atmospherical pressure will cause the wires 31 to be straightened out and the shaft 33 with the arm 32 to be turned in clock-wise direction in Figure 7-, while a decrease of the pressure will cause the angle formed by wires 31 to be reduced and the point 32 to be swung to the left in Figure 7. The tendency pointer is positioned opisforced'by the tooth at that moment actuating the arm towards the toothed wheel 25'; Itthe pointer'32is positioned close to its zero position it is forced by the edge of'mernber lll outwardsrv h 15 which in its middle position has; an unstable The zeroizing mechanism'known per se oper ates in the following manner., [During the rota-T f tion of the wheel 81in the direction'of the "arrow from the position shown in Figure .1 thessupport 6 in the one or the othenldirection- By way oi I example, @it I may "be assumed, that the pointer is f I thenpushed out to the right as sh Wn'infFigure-SJ;

The right hand pawl 45 meets thus byjits arm ll 'v thex rnemb'er' 52 f itheljpointer. which latter by means of the support l3 is prevented fromyielding for the pressure. i 1 The book M" of the pawl 4" 'is: thuSYpreVented from actuating the toothed wheel whereas; on the'other hand, the" other pawl iis iree and broughtotowards' the toothed wheel 1 and by its. hook?! jengages a corresponding tooth.

space; saidgpawl" thenjturning on ,its' pivot and 'moving thetoothed'wheel 2' one tooth pitch in a elock-wise' direction.- .LLBy turning thernicr'ornv eters screw i, -rigidly connected toitheywheel' 2 V e tl1rough ,-;its :shaft I and by. the resulting change i in the spring power ,actingupon the. diaphragm,

the diaphragm is shifted towards its middle posit; l tion; corresponding to the a-middle position got the tendencyvlrpointer. 'I 'hefjsai'd {middle position of -5 the diaphragm may thenbe passeds'o that the cuspidatedi member-l 210i pointer 32, after having 7 been released from' the arm l'lf 'upon the restore-5 tion of thesupport 65 may; deflect ina direction; opposite ;to that just ,described.;- Iffthe pressure 1 acting upon the diaphragm is' constant the tend-. en'cy pointer will thusfduringthe operation of" the zeroizing mechanism' alternatelydeflect on opposite sides oi the middle position-at the same 7 time as the toothed wheel isf alternately turned J one tooth pitchin eachdirection. Upon; a change;

by way of example an increase, in; the air "pressure, 7' he e l m o th ot er: hao fi l repeatedly actuated in one andpthesamqdirec-j 7 tion the ;counteracting ;spring power then being ;I altered in accordance with .the air pressure;

When the changeiri-air pressureyhas ceased the mechanism is restored-to the .starting'position'. in Whichthecounter spring thusfperiodically is subjected: tolalternategstretching and unstretching action for each turning ot-t 'etoothed wheel "2 joverlone toothpitch. 1 Y

An indicating pointer 39 adapted: to indicate;- the rate 1 of change in air pressure; p on a scale i 9. is connected with a disc: I? freelyunounted on. theshaft of themicrometerscrew 3ljw-hichdisc V opposite the pawl mechanism 4 4;"; is provided w a sme l n m j 'nm h i esentoc se, t ns:

fteeth t6. Eachof theteeth15 is-positioned op 1 n 9 het m-tq xthe oq hedW eel? but the teeth 16 have only about half }the-. height-- of theftfleethfi andezgtendsoutwa'rds only to; about t e mi o h et -J e h- 1179 he r ttl v to nogag'ethe teeth tithe hook l4 orfl', respectivelyv being. operatedlfor the 7 time I being ymnst thus I i penetrate morethan half way down intothe-op posite itooth space of the wheel-f2 sides'of the. rows of, teethz lfi" they; diametrically j opposite points, pro'vided -witha number ofl locking teeth" I! and l l respectively -w ih wh hwtw i et sI land, la; cooperate "Ofiith shaftfl to-Which is Al indicating the actual pressure on a'scale d2 9 Op os te 1. iS,1- at;

2,011,774 fi. 1 I saiddetents are pivoted on the respectively. I instrument frame at E9 and [9. respectively.

The detents rare actuatedbyspring'powertendenceof the disc l5: s The disc 55 is normally held in (Fig, 6)

an oscillating arm 28 is freely inounted'which,

under' the influence of a compression spring it its normal huddle position of rest bya spring 55' l infgi to press the detents; towards thecircumfersecured a pointer en'gaging'the end'oi a rear extension of said sidesf o f vthe symmetry plane' 'of the devicejand arm, may take up two end positions-on opposite equilibrium; At thefendpfythejarm facin the pawl mechanism thearm-jis providedrwith a tooth 22. of sucha width thatv it in each of the two i end-:positions of:the arm covers two teeth and the; intermediate tooth" space on each of the wheelsi2 and i5. Oneach side of'the tooth 22 the armisformed with abutments 23 m 23 hand position, a stud 24 disposed on a rear-ex: tension of the arm: then holding the fdetent l8 out of engagement with the corresponding teeth 'H".- by; bearing againstthe outer end of an arm "25f projecting tromgthedetent." A corresponding stud 25,; adapted; in' similar mannereto; cooperate l with theother, detent l8 ig-however, brought away from "the c'zorrespondin'garm-Z25 Ion the detent i8 whereby said arm under thefinfiuence on theoright hand side ef the toothedwheel i5.

In the position shown in Figure l on the, arm 26,

the righthand side abutment 23 .iis.fpositioned' opposite that tooth space of the toothed wheel 2 which is'oppositethe h'ook14$ For this reason 'said.-hook,. 1; actuated in this moment; would only penetrate half way into said tooth space and thus be prevented irorn engaging" the lower wheelgl 5.-

I, an explanation of v the operation of the dee t H 1 of l thespring power engages the locking .teethJ 1 415 t-is assumed. thatthe parts at a :certain moment take-up the positions shown in' Fig, 1

the ouspidated member of the tendency pointer 32 then," byway, of example, beingpositioned somewhat tol the left of the edge ofimember ID. When the support 5 is pushed' by the toothed, wheel. 8 towards the wheel Zthe pawl 4 will, in

above described mannerfbei'stopped bythemem berR' i 21 whereas the pawl 4f issfree to be brought towards the toothed wheel- 2, its'hool; {4' then penetratinginto the "corr'espending tooth space until it'reaches the abutment 23' of the'arm 29..

The-jzpawld is then turned on its pivott and shifts the wheel 2 over one tooth pitch [in a counte clockwise directionfand'catchesat the same time its arm 26 which, under theinfiuen'c'e ofj itsjs pring 2i, jerks past the middle position and is shittedintothe opposite end positio n.' The stud 24 then brings; the detent i 8 out of engagee ment with the locking teeth ll whereas instead l5 hasmeanwhile not been 'aiztuated because the hook l lo, a'smentioned abovejisfchecked by the abutment. 23 from "engaging the wheel) i5. If

,theair lpressureis unaltered the tendency :pointer ,i v the detentl 8 by thespring power is brought into engagement with the locking teeth ll; Thedisc 32 is now, on account of the change inthe'tension' o oi the counter springacting, 0111 the diaphragm, V moved-somewhat to the right of :the middle positiorpgas soon ;as said pointer; has: been released pitch corresponds to a certain altitude change.

instead of a certain change in pressure.

p I claimz 1. An instrument for indicating the rate of change of variable forces comprising in combination a measuring member movable under the influence of the variable forces,'a counter-spring acting upon the measuring member, a resetting mechanism including means to vary the tension of the counter-spring, driving means, means under control of the measuring member .for imparting intermittently resetting impulses, from said driving means to the resetting mechanism, the direction of resetting being under the control 1 of the measuring member, an indicating member movable independently of the measuring member and adapted to be set stepwise from a middle position in connection withsaid resetting mechanism, and means for restoring saidindicating member to a middle position upon a change i the resetting direction; 2. An instrument for indicating the rate of change of variable forces comprising in combinationa measuring member movable under the influence of the variable forces, a counter-spring acting upon the measuring member, a resetting 'mechanism including means to vary the tension ,of the counter-spring, driving means, means under the control of the measuring member for imparting intermittently resetting impulses, from i said driving means to the resetting mechanism,

' the direction of resetting being under the control of the measuring member, anindicating member movable independently of the measuring member and adapted to be set stepwise from a middle position in connection with said resetting mechanism, a control member adapted to be shifted from one'control position to another upon a change in the resetting direction, and means for restoring the indicating member to a middle position upon a shifting of the control member.

3. An instrument for indicating the rate of change of variable forces comprising in combination 'a'measuring member movable under the influence of the variable forces, a counter-spring acting, upon the measuring member, a resetting 1 mechanism including means to vary the tension [of the counter-spring, an indicating member.

movable independently of the measuring member and adapted to be set stepwise from a middle position of rest, a driving device, means for transmitting intermittent resetting impulses from said driving device to the resetting mechanism and for transmitting setting impulses from the driving device to the'indicating member, the direction of resetting being under the control of the measurtransmitting setting impulses from the driving deing member, and means for restoring said indicat- "ing member to a middle position upon a change in the resetting direction. V

r a. An instrument for indicating the rate of change of variable forces comprising in combi nation a measuring member movable under the influence of the variable forces, a counter-spring acting upon the measuring member, a resetting mechanism-including means to vary the tension of thecounter-spring, an indicating member 'movable independently of the measuring member and-adapted to be set stepwise from a middle position of rest, a driving device, means for transmitting intermittent resetting impulses from said driving device to the resetting mechanism and for locking means upon a change of the vice to the indicating member, the direction of re- I setting being under the control of the measuring member, a control member under the control of the impulse transmitting means adapted to be shifted from one control position to another upon a'change in the resetting direction, means under the control of said control member for limiting the direction of movement of the indicating member, and other means for restoring the indicating member to a middle position upon a shifting of the control member.

5. An instrument for indicating the rate of' change of variable forces comprising in combination a measuring member movable under the influence of the variable forces, a counter-spring acting upon the measuring member, a resetting mechanism comprising a stepwise rotatable re-,

setting wheel, a. rotatable indicating member freely mounted coaxially with ,said resetting I wheel, a driving deviceymeans for transmitting intermittent rotary impulses to the resetting wheel and the indicating member, the direction of rotation of the resetting wheel being under the control of the measuring member, and resilient means tending to restore the indicating member to middle position, locking means for retaining the indicating member in the position set by said rotary impulses and means for unlocking said direction of rotation of the resetting wheel. i

6. An instrument for indicating the rate of change of variable forces comprising in combination a measuring member movable under the insilient means tending to restore the indicating member to middle position, locking meansfor retaining theindicating member in the position set by said rotary impulses, and means under control of said control member for unlocking said locking means.

7. An instrument as claimed in claim 6, characterized in that the locking means comprises two detents adapted to engage the indicating member alternately under the control of the control member. 1

8. An instrument as claimed in claim 6, in whichsaid impulse transmitting means comprises two impulse transmitting pawls adapted to cofluenceof the variable forces, a counter-spring acting upon the measuring member, a resetting. mechanism comprising a step-wise rotatable reoperate, under the control of the measuring member, alternately with a toothing at the circumference of the resetting wheel, the indicating member being also provided with a toothing coaxial with said first toothing but having a smaller diameter, the movement of the one or the other pawls, according to the position of the control member, being limited in radial direction by an abutment on the control member so as to prevent the engagement of the second toothing by the pawl.

JOSUA GABRIEL Prunin 

